1. Technical Field
The present invention relates to an exchangeable cylinder type rotary press, which is driven via a driving shaft by a single prime mover and which is capable of conventional printing in an inch standard (with inch used as size unit) but which is also adapted for printing in a millimeter standard (with millimeter used as size unit), or printing in any top-bottom length as desired, independent of a power transmission system from the prime mover.
2. Description of the Prior Art
FIG. 1 is a view illustrating an example of the exchangeable cylinder type rotary press (hereinafter referred to simply as “rotary press”) as seen from the side of the prime mover. The rotary press is equipped in turn from the upstream side of travel of rotary printing paper 1 with a paper feeder 2, a printing section 3 and a machining section 4. Supplied from the paper feeder 2, rotary printing paper 1 is printed as desired in the printing section 3 and then machined as desired in the machining section 4 in which for example, longitudinal-perforating, file punching, lateral-perforating and sheet cutting are performed at a longitudinal-perforating unit 4a, a file punching unit 4b, a lateral-perforating unit 4c and a sheet cutting unit 4d, respectively, the rotary printing paper being thereafter discharged. The printing section 3 here comprises a plurality of, e. g., four, printing units, 3a, 3b, 3c and 3d, each of which has a three-cylinder exchangeable, exchange cylinder unit 12 removably mounted thereon comprising a printing cylinder 9, a blanket cylinder 10 and an impression cylinder 11. Further, a paper feed roller 13a and a machining section tension roller 13b are provided, constituting a rotary printing paper feed means.
And, driven parts in this rotary press are coupled to their respective power transmission drives 14, 14, . . . on the side of the machine frame, all of which are coupled via a driving shaft 15 to a single prime mover 16 so that all these driven parts may be synchronously driven by the single prime mover 16 via the driving shaft 15 and the respective power transmission drives 14.
Further, in the rotary press of this type, rotary printing paper 1 may also bypass the machining section 4 and be directly wound and processed on a take-up section 2a. 
The printing units 3a to 3d are of an identical construction, one of which, e. g., printing unit 3a, has a power transmission system as shown in FIG. 2. In the printing unit 3a, rotation of the power transmission drive 14 is transferred via a gear train 17 to a driving gear 18 mounted on the principal machine side. And, with the three-cylinder exchangeable, exchange cylinder unit 12 mounted on the printing unit 12a, a driven gear 19 of the printing cylinder 9 mounted coaxially with the printing cylinder 9 is engaged with its driving gear 18 for driving the exchange cylinder unit 12. Further, The blanket cylinder 10 and the impression cylinder 11 have their respective driven gears 20 and 21 which are mounted coaxially with them, respectively, so as to serially engage the driven gear 19 of the printing cylinder 9.
The driven gear 19, 20, 21 has a pitch circumferential length (or pitch circle diameter) which is identical to a peripheral length (or diameter) of the cylinders 9, 10 and 11. And, when driven by the driving gear 18, the driven gears 19, 20 and 21 are rotated in their respective pitch circumferences at a speed which is identical to a rate of travel of rotary printing paper 1 determined by rotation of the prime mover 16. And, continuous paper 1 passing between the blanket and impression cylinders 10 and 11 rotated together with them is drive to travel at the abovementioned speed of travel.
And, a rotary press of this type has been made in inch as size unit and thus the driving gear 18 has been made in inch as size unit and accordingly the driven gears 19, 20 and 21 of the cylinders of the exchange cylinder units 12 have been made in inch as size unit.
In such a rotary press, if its driving gear 18 used is a gear whose CP (circular pitch) is ¼ to print in a top-bottom length of 22 inches, as an example the driven gear 19, 20, 21 used of the cylinder 9, 10, 11 may be a gear whose number of teeth is 88 (=22×4) such as to print in the top-bottom length of 22 inches each time the cylinder 9, 10, 11 makes one rotation.
By the way, it has recently become frequent that the rotary press of this type is required of printing in a millimeter standard. Under such circumstances, if a conventional rotary press which corresponds to an inch unit is used to print in a millimeter standard, a wasteful, non-printed portion has appeared on printed paper and it has entailed troublesome operations to remove the non-printed portion.
For example, if a print having a top-bottom length of 555 mm is to be printed, a rotary cylinder for printing in a top-bottom length of 22 inches must have a peripheral length in millimeter size of 22×25.4=558.8 mm and must produce a non-printed portion of 3.6 mm in the top-bottom direction.
In order to get rid of such a non-printed portion, one might use a cylinder whose peripheral length if made in inch as its size length is close to 555 mm. It has not been possible, however, to make the pitch circle diameter of the driven gear provided for this cylinder coincident with the outer diameter of the above-mentioned cylinder.
As a result, in order to print a print of A4 size having a top-bottom length of 297 mm, one may use a gear having six teeth per inch pitch-circumferentially, namely having a CP of ⅙ and having 70 teeth, thus a gear having a pitch circumferential length of (⅙×70=11+⅔ inches) or 296.33 mm and a cylinder of a peripheral length identical to the latter. Then, the printing size obtained is an approximate size; there remain the problem that an accurate A4 printing size is not obtained.
Accordingly, of conventional rotary presses of this type, one have also been known (see, e. g., JP S58-138649 A) using a printing cylinder and a driven gear mounted coaxially thereof which are both with a millimeter standard and wherein the driven gear has a number of teeth made proper so that it can tune with a driving gear on the principal machine side.
In the preceding prior art, if the cylinders in a cylinder exchange unit are of a millimeter standard, the drive source for driving the exchange cylinder unit is of an inch standard so that the circular pitch of the gears on the driving and driven sides must be ¼, ⅙, ⅛, 1/10 inch or the like. As a result, only prints of printing lengths which are integral multiples of such a circular pitch can be printed; hence poor in flexibility. Also, in the case of printing on approximate values to millimeter standard sizes, there are limits in number of applicable gear trains so that no print can aptly be printed but on particular sizes. Also, depending on sizes, the circular pitch of a gear used may become small to an extent that the gear must have strength less than as needed. Furthermore, the limitation in numbers of applicable gear trains gives rise, e. g., to the problem that no print can be made but on sizes of a selected dimensional series.
With these problems taken into account, it is an object of the present invention to provide an exchangeable cylinder type rotary press which if designed on printing in an inch standard can, unrestricted thereby, be used on printing in a millimeter standard, which if designed on printing in any particular unit standard is capable of printing upon exchanging cylinders to those of any top-bottom length as desired, which allows the size of such cylinders to be freely set and which further permits, in addition to an exchange cylinder unit having any such top-bottom length as desired, an exchange cylinder unit, e. g., with an conventional inch unit standard to be used.